NEW YORK (Reuters Health) - Music therapy might help lower anxiety and improve mood in people with cancer, say researchers who analyzed past studies.

It's not entirely clear from those studies what kind of music-related treatment -- going to sessions with a music therapist, or listening to pre-recorded CDs during hospital visits -- might help patients most.

But music therapist Debra Burns, from Indiana University-Purdue University Indianapolis, said therapists especially can help patients relax during stressful treatments and think through their tension.

"We can use the different music interventions to target the in-the-moment symptoms -- pain, anxiety. But we can also look at longer-term interventions," such as improving communication with family members, said Burns, who was not involved in the review.

For the analysis, creative arts therapist Joke Bradt from Drexel University in Philadelphia and her colleagues reviewed data from 30 past studies that looked at the effect of music therapy or music listening in close to 2,000 cancer patients.

Compared to patients who only received standard cancer treatment, the combined data from the studies suggested that patients who also had music treatment rated their anxiety and pain lower and had higher mood scores. In addition, their heart rates were lower by about four beats per minute, on average.

There was no effect, however, on how patients rated their depression or fatigue.

That's probably because most of the studies only tested the effect of listening to music in the hospital for a single session, and didn't give patients much choice about what type of music they listened to, Bradt said.

"If someone's really depressed, one music listening session is not going to reverse that," she told Reuters Health.

While there wasn't enough data to determine if going to a music therapist helped patients more than listening to CDs, Bradt said she suspects that's the case. With a music therapist, patients are usually involved in making music by singing or playing instruments, she explained, and therapists can design a treatment program for each particular patient.

"The patient can become an active participant," she said. "It can be really empowering, and can help patients feel more in control over the situation."

Burns agreed. Therapists can adapt treatment "as they need to depending on the patient's needs. It gives you some flexibility and a wider breath of tools," she said.

"We cannot forget that making music is a lot of fun as well," Bradt added.

It can be hard to objectively compare anxiety and depression in patients getting music therapy and those not getting any extra treatment, the authors explained in the new review, published in the Cochrane Library. That's because researchers can't keep music therapy a secret from patients -- so if patients think music therapy will help them, they could feel better just because of that extra optimism and expectation, rather than the because of the therapy itself.

But Bradt said despite that limitation, the potential positive effects of music treatment -- especially with a trained music therapist -- should be taken seriously, and that it's not "just about listening to some music."

"Certainly it's not for everybody," said Burns, who's on the staff of Indiana University's Melvin and Bren Simon Cancer Center.

"Somebody at least has to be open to the experience," she told Reuters Health.

Burns concluded that research should continue to look at what type of music therapy might help different patients at different stages of their cancer treatment.